Homeland Security Secretary Kirstjen Nielsen has told Mexican authorities that National Guard troops deployed on the border would not be armed or participate in immigration or customs duties, according to the Mexican Foreign Ministry.
Nielsen's plan, though still vague, would use state Guard units in support roles, in accordance with U.S. law, resembling the two recent deployments from Presidents Barack Obama and George W. Bush.
Mexico said it has emphasized to the Trump administration that if the deployment comes to resemble a militarization of the border, "it will gravely damage the bilateral relationship."
President Donald Trump has spent several days warning of a growing crisis on the border even though illegal immigration is at its lowest level in decades. He has repeatedly accused Mexico of doing too little to stop migrants from Central America.
The plan to use National Guard units was arranged hastily after Trump _ who has been frustrated with his inability to get Congress or Mexico to pay for a border wall _ said publicly this week that he wanted to use the military to patrol the border until the wall is built.
On Thursday, he offered praise for Mexican officials for stopping "the caravan" of about 1,000 mostly Central American migrants from entering the United States. Spurred by media reports of the migrants, who are in the southern Mexican state of Oaxaca, Trump has blasted the caravan in recent days.
Trump's tweet also celebrated the overall drop in illegal border crossings, but still called them "UNACCEPTABLE."
The dual message underscores the challenge Trump faces in declaring an emergency at the border to secure Guard troops, in what critics say is a manufactured crisis.
